Hydrochloric Acid → 2-(N,N-dimethylsulphamoyl)benzeneboronic acid

Temperature

-70 °C

A solution of N,N-dimethylbenzenesulfonamide (9.25 g; 50 mmol) in dry Et2O (150 ml) under N2 was cooled to −70° C. and added a solution of 2.5 M n-BuLi in hexane (24 ml; 60 mmol) such that the reaction temperature was kept below −60° C. The cooling bath was removed and the reaction mixture allowed to slowly warm up to +20° C. The reaction mixture was re-cooled to −70° C. and B(Oi-Pr)3 (16.1 ml; 70 mmol) was added. The reaction mixture was left cold and allowed to warm up over night, 1 M HCl (100 ml) was added and stirring was continued at rt. for 1 h. The reaction mixture was then extracted with Et2O (2×50 ml) and the combined organic fractions extracted with 1 M NaOH (4×50 ml). The combined aqueous fractions were neutralized with 1 M HCl and extracted with Et2O (4×100 ml). The combined organic fractions were dried (Na2SO4) and evaporated to dryness, washed with Et2O/hexane to give 3.4 g (30%) product.

1. customwas kept below −60° C
2. customThe cooling bath was removed
3. temperatureto slowly warm up to +20° C
4. waitThe reaction mixture was left cold
5. temperatureto warm up over night
6. customwas continued at rt
7. extractionThe reaction mixture was then extracted with Et2O (2×50 ml)
8. extractionthe combined organic fractions extracted with 1 M NaOH (4×50 ml)
9. extractionextracted with Et2O (4×100 ml)
10. dry with materialThe combined organic fractions were dried (Na2SO4)
11. customevaporated to dryness
12. washwashed with Et2O/hexane

ORD record

ord-8ea65a99d7f74ecb9f407694ee52ef25

Source dataset

uspto-grants-2007_06

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US07235548B2